Question

The carbohydrates seen here contain three common elements. They are

Answer 1

seen where?

Answer 2

Carbohydrates are made of carbon, and contains hydrogen and oxygen atoms. Carbon is the base atom and oxygen, and hydrogen is bonded to the carbon. The ratio of hydrogen to oxygen is 2:1.

Answer 3

We'd really have to see the image. Carbohydrates are made of monomers of monosaccharides (single simple sugars) and these monomers are linked by a specific type of bond called a glyosidic linkage.

Answer 4

Possibly reading too much into the question? Maybe they want C, H and O